HEAT CAPACITY AND CALORIFIC INTENSITY CURVES 357
are experienced in starting up regenerative furnaces where the
operator has been unfamiliar with producer gas.
Table 8 gives the heat capacities of the usual gases found in the
products of combustion as determined by the formulas developed
by Mallard and Le Chatelier. These formulas, given in Table 10,
were used in computing the heat capacities of the gases at intervals
of 200° C. (360° F.) between 0° C. (32° F.) and 2600° C. (4712° P.)
which are given in Table 8.
At the bottom of Table 1 there have been collected and
totalized the numerical values used in the second column of
Table 3 designated by the symbols N2+ and N2. These gases
have the same heat capacity per gram molecule as given in the
second column of Table 8. This procedure simplifies the com-
putation. The other numerical values in the second column of
Table 3 were brought forward from Tables 1 and 2. These
numerical values, designating the number of gram molecules in
the products of combustion, were then multiplied by the heat
capacity values given in Table 8 and the products for steps of
400° C. (720° F.) were tabulated in columns three to nine, inclu-
sive, of Table 3. The points for the curves were obtained by the
summation of these values for the appropriate combustion condi-
tions. These points were then plotted and connected by curved
lines giving a number of diverging parabolas indicated by the
solid black lines, each of which is marked by a percentage value
designating the air supply conditions which influenced the forma-
tion of the products of combustion.
Table 4 shows a similar computation made to obtain the heat
capacity of the gas itself and the air supplies.
The heat capacity of the gas is plotted in dash lines and that
of the air supplies in dot-dash lines, these last being marked with
the percentage values of the air supply.
The next step in the plotting of these curves is the spotting of
the points denoting the amount of heat released by the combustion
of the gas, with 60, 80 and 100 per cent air supply. The values
marked /, F and A in Table 5 give the summations of the number
of calories released by the gas as given in Table 1, where they are
marked with the same reference letters. From this point on, the
plotting may be done graphically or by computing the points as
in Table 5. When the points /, F and A have been spotted, a line
parallel to the temperature scale is drawn downward crossing all